w3m: Avoid depending on libgc-dev when building

packages/w3m/Makefile.in.patch

@@ -1,6 +1,6 @@
 diff -u -r ../w3m-0.5.3/Makefile.in ./Makefile.in
 --- ../w3m-0.5.3/Makefile.in	2011-01-04 04:22:18.000000000 -0500
-+++ ./Makefile.in	2015-11-19 17:27:59.073507125 -0500
++++ ./Makefile.in	2016-05-12 16:53:44.113699285 -0400
 @@ -176,8 +176,8 @@
  	./mktable$(EXT) 100 functable.tab > $@
  	-rm -f functable.tab
@@ -8,7 +8,7 @@ diff -u -r ../w3m-0.5.3/Makefile.in ./Makefile.in
 -mktable$(EXT): mktable.o dummy.o Str.o hash.o myctype.o
 -	$(CC) $(CFLAGS) -o mktable mktable.o dummy.o Str.o hash.o myctype.o $(LDFLAGS) $(LIBS) $(GC_LIBS)
 +mktable$(EXT): mktable.c Str.c hash.c myctype.c
-+	gcc -DGC_free=free -DGC_malloc=malloc -DGC_malloc_atomic=malloc -D'GC_init(arg)=' -o mktable mktable.c Str.c hash.c myctype.c
++	gcc -isystem $(TERMUX_PKG_BUILDER_DIR) -o mktable mktable.c Str.c hash.c myctype.c
  
  $(BOOKMARKER): w3mbookmark.o dummy.o $(ALIB)
  	$(CC) $(CFLAGS) -o $(BOOKMARKER) w3mbookmark.o dummy.o $(LDFLAGS) $(LIBS) $(EXT_LIBS)

packages/w3m/build.sh

@@ -7,3 +7,6 @@ TERMUX_PKG_DEPENDS="libgc, ncurses, openssl"
 # ac_cv_func_bcopy=yes to avoid w3m defining it's own bcopy function, which
 # breaks 64-bit builds where NDK headers define bcopy as a mactro:
 TERMUX_PKG_EXTRA_CONFIGURE_ARGS="ac_cv_func_setpgrp_void=yes ac_cv_func_bcopy=yes"
+
+# For Makefile.in.patch:
+export TERMUX_PKG_BUILDER_DIR

packages/w3m/gc.h

@@ -0,0 +1,8 @@
+/* A stub for gc.h to avoid depending on libgc for
+   the host-built mktable program. */
+#define GC_INIT()
+#define GC_MALLOC(arg) malloc(arg)
+#define GC_malloc(arg) malloc(arg)
+#define GC_MALLOC_ATOMIC(arg) malloc(arg)
+
+#define GC_free(arg) free(arg)